Method of digging manholes



Nov. 10, 1970 I w. Hl 3,538,629

' METHOD OF DIGGING MANHOLES Filed Nov. 16. 1967 2 Sheets-Sheet 1 INVENTOR. CHARLES W. HEMPHILL BY MARCUS L. BATES Nov. 10, 1970 c. w. HEMPHILL METHOD OF DIGGING MANHOLES 2 Sheets-Sheet 2 Filed Nov. 16, 1967 INVENTOR. CHARLES W. HEMPHILL BY MARCUS L. BATES United States Patent Olfice 3,538,629 METHOD OF DIGGING MANHOLES Charles W. Hemphill, Lubbock, Tex. (Rte. 2, Box 30A, Ben Wheeler, Tex. 75754) Filed Nov. 16, 1967, Ser. No. 683,523 Int. Cl. E02f 1/00, 5/20 US. Cl. 37-195 3 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Nowadays, ditches are seldom dug using manual labor. Modern ditch digging art has progressed at an astonishing pace, and from the smallest ditch, which may be only a foot in depth and two inches wide, up to the largest ditch which may be more than five feet wide and forty feet deep, mans ingenuity has devised various machines for accomplishing the digging, laying of wire or pipe, and for fabricating tunnels or canals. In digging ditches for laying pipe for a sewer which must flow by gravity, it is often necessary to dig the ditch to a vertical depth exceeding forty feet. This pipe is laid onto the bottom of the ditch and the ditch again covered. This entire operation usually proceeds in an orderly fashion with the ditch being both dug and covered as a single operation with only a short distance of the ditch being left open at any time. Manholes are generally placed at least each thousand feet of length along the sewer line in order to provide a means for cleaning the sewer as well as for general maintenance of the line. Manholes must also be placed along certain designated streets or dedicated areas where future development may require a lateral tie-in at a later date.

Manholes are expensive to dig. The manhole vertically depends upwardly from the sewer pipe and installation of a twelve inch inside diameter clay pipe may require digging a five foot diameter hole in order to properly fabricate the reinforcing sides of the manhole. Accordingly, fabrication of the manhole by present art expedients not only retards the orderly work of the contractor, but also is expensive since it usually involves an excessive amount of manual labor.

SUMMARY OF THE INVENTION The present invention relates to both a method and apparatus for constructing or fabricating a manhole. The invention is specifically directed to constructing a vertical manhole at spaced apart locations along a ditch which has been previously dug and which is to be provided with a pipe or sewer line. The present invention enables the excavation of manholes of any size which is consistent with the specific ditching machine utilized to construct a specific ditch, as will be better understood after reading the remainder of this disclosure.

One specific embodiment of the present invention utilizes spaced apart side digging wheels which are removably attached to the rotatable wheel of a ditching machine. The ditching machine may be of the wheel type or it may be of the endless or ladder type. In any event, the main rotat- 3,538,529 Patented Nov. 10, 1970 able wheel is provided with means for removably attaching contoured side diggers thereto. The side diggers are bowl shaped and are provided with a multiplicity of spaced apart teeth whereby rotation of the rotatable wheel imparts rotational movement to the side diggers to thereby enable the teeth to dig into the earth. The configuration of the side diggers controls the curvature of the manhole.

The utilization of the specific embodiments of the apparatus set forth in the present invention necessarily involves a neW method for providing manholes. The method includes the provision of the above mentioned side diggers in conjunction with a rotatable wheel with the wheel being vertically adjustable so as to enable the side diggers to be lowered as they remove earth from the terrain. The resulting geometrical pattern of the removed soil provides a vertically dug depression which results in the formation of a manhole.

It is therefore a primary object of the present invention to provide a method of constructing manholes in the ground.

Another object of the present invention is to provide a method whereby a hole may be dug along a previously formed ditch in order to provide ample working space for constructing a manhole.

A further object of the present invention is the provision of a method of digging holes in the ground for the purpose of interconnecting the bottom of a ditch with the surface of the ground and with the hole being of a sufficient diameter to enable workmen to fabricate the necessary structure in order to form a permanent manhole.

A still further object of the present invention is the provision of a means for digging a hole into the ground by utilizing dished shaped digging means attached to a rotatable wheel.

A still further object of the present invention is the provision of a mechanism for digging holes into the earth.

A still further object of the present invention is the provision of a digging apparatus which forms vertical holes at spaced apart locations along a previously constructed ditch to thereby enable the hole to be conveniently reinforced by side walls which are fabricated Within the vertically extending hole.

A further object of the present invention is the provi sion of an apparatus which may be readily attached to an existing digging machine to thereby enable the machine to construct a vertically extending hole in the surface of the earth, whereby a conventional manhole may be fabricated within the formed hole.

Some of the above objects are attained in, accordance with the present invention !by the provision of spaced apart side diggers which are removably afiixed to a conventional ditching machine in accordance with the teachings of the instant disclosure.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a ditching machine as it digs a ditch into the ground in order to provide a trench in which a pipe line is laid, and shows part of a manhole which has been dug in accordance with the teachings of the present invention;

FIG. 2 digrammatically illustrates one prior art method of partially fabricating a manhole;

FIG. 3 is an enlarged fragmentary representation of a part of the equipment seen in FIG. 1;

FIG. 4 is a fragmentary cross-sectional View taken along line 4-4 of FIG. 3

FIG. 5 is an end view of the device seen in FIG. 4;

FIG. 6 is an opposite end view of the device seen in FIG. 5;

FIG. 7 is a cross-sectional view taken along line 77 of FIG. 4;

FIG. 8 is an enlarged cross-sectional view taken along line 8-8 of FIG.

FIG. 9 is a cross-sectional view showing a modification of the device seen in the foregoing figures, which could have been taken along line 9-9 of FIG. 4;

FIG. 10 is a cross-sectional view taken along line 1010 of FIG. 11; and

FIG. 11 shows a modification of one of the side diggers which is similar in many respects to the device illustrated in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Throughout the remainder of this specification, like numerals generally refer to like or similar parts.

Looking first to the illustration of FIGS. 1 and 2, there is seen a track mounted ditching machine 12 having a rearwardly and downwardly projecting boom 14 which is removing or digging earth at 15 so as to provide a ditch 16. The ditch is being back-filled at 18 in order to cover sewer pipe 19 and to restore the appearance of the terrain. A vertically extending manhole 20 communicates the bottom of the ditch with the surface of the ground. The device which excavated the vertically extending manhole 20 is seen lying on the ground at 45.

Looking now to the diagrammatical representation of FIG. 2 there is seen illustrated another ditch 10 which extends cross-country and which has been cross-cut with two ditches 22, 24 of limited length so as to provide an enlarged area away from the cross-cut at 26 which can be further excavated to provide a vertically extending manhole by utilizing a substantial amount of equipment and labor. This particular expedient belongs to the prior art.

Turing now more particularly to the details of the present invention, there is seen illustrated in FIG. 3 the depending end of a conventional endless or ladder type ditching machine generally illustrated by the arrow at numeral 28. The ditching machine includes a rotatable wheel 30 which is suitably journaled to a cantilever boom with the boom being built up of steel beams 32 in the usual manner. An endles chain 34 is driven from the power unit 12 with the chain being suitably suspended between the rotatable wheel 30 and the driving wheel (not shown) by a multiplicity of spaced apart idler rollers 36 suitably journaled to the boom. Digging means 38, in the form of a multiplicity of toothed buckets, are spaced along the end less chain in order to both dig and convey the removed earth to a location away from the ditch. The chain is received by the rim 40, 42 of the rotating wheel with the wheel prescribing a circumference indicated by the arrow at numeral 44. Numeral 46 indicates the digging range of the side diggers which preferably is greater than that of the buckets and which presently will be discussed in greater detail. The conventional rotating Wheel 30 has an outer plate thereon which has been modified by the provision of the deformed eyelets 48.

While an endless type or ladder type ditching machine has been selected in order to describe the present method and apparatus, it should be understood that the rotatable wheel 30 may also be of the large Wheel type ditching machine wherein the buckets 38 are attached to a large rotating wheel rather than to an endless conveyor 34.

Looking now to the details of FIGS. 4 through 8 there is seen the before mentioned rotating wheel having the deformed eyelets radially spaced circumferentially about the wheel-and with the wheel being attached to a main shaft located within housing 50. The side digger, shown disengaged from the wheel 30, includes a support ring 52 in the form of a rail which is circumferentially disposed about hub 54 by means of four radiating spokes 56. Also depending from the support ring are a multiplicity of bowed spokes 58 which are centrally attached to the bow support pad 60. Stand-off member 57 maintains the bows properly spaced apart from the hub. The hub includes a cylindrical body portion 62 having a circumferentially extending flange 64 outwardly depending from the edge portion of the body portion 62. Bolts 68 are welded to the marginal edge portion of the flange and placed in alignment with the deformed eyelets with the heads of the bolts being of a size to be received through the eyelets and with the smaller part of the eyelet being of a size to slidably receive the bolt body; whereupon insertion of the bolt head through the larger part of the eyelet with subsequent rotation of the side digger will properly align the side digger with the rotating wheel. The details of the side digger located on the opposite side of the main shaft housing will not be discussed in detail since it is fabricated identically (except for the relative position of the teeth) to the foregoing side digger.

As seen in FIGS. 5 and 8, mounts 70 are each adapted to removably receive digging teeth 71 therein, with the mount preferably being welded directly to the bowed spoke 58. The digging teeth of one bowed spoke are misaligned with the teeth of the adjacent spokes as illustrated at 70 and 71 in FIG. 5. This arrangement permits each adjacent set of teeth to dig in a different location with respect to its adjacent teeth. It should be understood that each bowed spoke is slightl twisted from its normal plane in order to augment the action of the teeth by scraping the Walls of the hole with one edge portion thereof.

Looking now to the details of FIGS. 9 through 11, wherein there is seen a modification of the side diggers. In this modification the main shaft 84 is rotatably received within housing 50; with housing 50 including the mounting plate 51 in order to rotatably mount the rotatable wheel to the cantilever boom. Shaft 84 is driven in the usual manner by the endless chain 34. The shaft receives a centrally located passageway which for purposes of illustration is shown to be square in geometrical configuration. The hollow shaft 84 is of a size to slidably re ceive drive cross-shaft 76 in tight fitting relationship therethrough. As seen in FIG. 11, the drive cross-shaft may be slidably extended through the main shaft and pinned at 78 to the stand-off 57 by means of pin 80. Circumferentially extending flange 64 need not be provided with bolts 68 as in FIG. 4 because it is now an idler flange since it merely abuts against and rotates with the rotatable wheel 30. The rotatable wheel 30 is apertured as seen at 82 in order to receive the cross-shaft 76 therethrough.

It should be understood that while eight bowed spokes in conjunction with four radiating spokes are utilized in the structure of the side digger, it is possible to vary the number of each of these spokes as well as their relative position with respect to each other.

OPERATION In operation the ditching machine continues to excavate the ditch While the pipe is being laid therein and the ditch being back-filled, all in a manner as illustrated in FIG. 1. Upon reaching the location where a manhole must be connected to the pipe 19, the operation will appear as seen in FIG. 1 with the exception that the manhole 20 will not yet have been excavated. The boom of the ditching machine, assuming a ladder type ditching machine is being utilized, is lifted from the bottom of the ditch and the side diggers installed thereon. Since the side diggers provide an overall width of the device which is much greater than the width of the ditch, the boom, after installation of the side diggers, can only be lowered to approximately ground level for the reason that the teeth located on the side diggers begin to dig into the ground. This action cause the vertical manhole to commence being formed, beginning at ground level, and with the earth which is loosened falling to the bottom of the ditch 16. The side diggers are maintained in proper vertical alignment by fore or aft travel of the machine in order to provide a vertical rather than arcuate manhole. This proper alignment is easily maintained by an observer, generally the foreman of the job, by his standing adjacent the proposed manhole and sighting an imaginary point on the opposite wall of the formed portion of the manhole as it is being dug. By occasionally directing the operator of the ditching machine to move forward or backward the vertical position of the manhole may be maintained extremely accurate. As the side diggers approach the bottom of the manhole, the digging means or buckets 38 will begin to excavate the previously loosened dirt in the usual manner. A single workman can stand in the bottom of the ditch and shovel any excess earth into close proximity of the bucket in order to remove all of the excavated earth during the final stage of digging the manhole. When the manhole bottoms at the lower ex tremity of the ditch, the boom is lifted from the bottom thereof, the side diggers removed, whereupon excavation continues as before. Alternatively, the side diggers may be left in the bottom of the ditch from which they are later removed. In order to install the side diggers onto the rotatable wheel, and again assuming a ladder type ditching machine, the side diggers are lifted by merely running a cable around one of the spokes or support ring whereupon the fiange on the hub can be abutted against the outer plate member of the rotatable wheel with the boltheads protruding through the enlarged portion of the deformed eyelets. With the side digger in this position, a workman can stand on one of the bowed spokes to force the side digger in a counterclockwise direction in order to rotatably force the threaded portion of the bolts into the smaller portion of the deformed eyelets, assuming the side digger is being installed on the side of the rotatable wheel as seen in FIG. 3. The nuts at 68 are then tightened in order to secure the flange 64 of the side digger abutted to the plate member of the rotatable wheel. The opposite side digger is installed in a similar manner whereupon the digging operation of the manhole can then commence.

In the installation of the embodiment seen in FIGS. 9 through 11, the side digger may again be lifted by the support ring 52 with the cross-shaft 76 being pinned within one of the stand-offs 57 and with the opposite side digger being removed from the cross-shaft. The cross-shaft is slidably inserted through the aperture located within each of the rotatable wheels, whereupon the cross-shaft extends through each wheel, through the main shaft bearing housing, as well as through the driven shaft 84. The remaining side digger is placed on the opposite side of the boom, secured into position by means of pin 80, and the digging operation may then begin. The square configuration of shaft 84 imparts rotational movement to each side digger by means of the square driven cross-shaft 76. It is within the comprehension of this invention to use splined shafts, hexagon shafts, as well as any other means of imparting rotational motion into the side diggers by taking advantage of the rotational motion of the rotatable wheel 30. The side diggers are removed by reversing the above procedure. It is advantageous to provide a dust cover plate over the aperture 82 when the side diggers are not installed.

In laying twelve to fifteen inch clay pipe in a thirtyeight inch wide ditch which is twenty-four feet deep, a five foot diameter manhole can be excavated in less than thirty minutes by using the method and apparatus of the present invention. When the side diggers encounter large rocks or exceptionally hard earth, the endless chain 34 will slip with respect to the rotatable wheel 30 thereby preventing damage to the side diggers as well as the remainder of the equipment.

Having read the foregoing description, it will now become evident to those skilled in the art to use the present invention in several different ways which may differ in some respects from the present disclosure. It is contemplated to utilize the invention in digging holes along a predetermined route of a proposed pipe line, to dig spaced apart holes along a previously formed ditch; as well as to dig holes simultaneously or in conjunction with the ditching operation. Furthermore, the invention may be used to form an underground enlarged tunnel which is connected to the surface by the narrow slit or ditch formed by the digging conveyor. This latter expedient is especially useful in the construction of sewers located below the thirty foot level.

I claim:

1. A method of excavating manholes with a ditching machine, wherein the ditching machine includes a rotatable wheel for rotatably carrying digging means in a circular direction thereabout so as to remove a predetermined portion of earth to form a ditch, and wherein outwardly disposed side diggers may be removably attached to opp f)site sides of the rotatable wheel, comprising the steps 0 1) digging an upwardly opening ditch by removing an elongated portion of earth with the digging means located on the ditching machine;

(2) attaching side diggers in juxtaposition relationship to the rotatable wheel, with the side diggers being arranged laterally with respect to the ditch, and axially with respect to the rotatable wheel;

(3) laterally aligning the side diggers with the previously formed ditch of step 1) whereby each of the side diggers outwardly overhang the earth forming side walls of the ditch, and the digging means is received Within the ditch;

(4) removing a portion of the earth which forms the sides of the ditch by engaging the earth with the rotating side diggers while maintaining the side diggers vertically aligned with respect to the bottom of the ditch by longitudinal movement of the ditching machine;

(5) continuing step (4) until an upwardly opening excavation having vertical side walls is formed which is of suflicient size to accommodate a manhole.

2. The method of claim 1, and further including the steps of:

(6) removing excess earth from the ditch which results from the operation of the side diggers;

(7) installing a pipe parallel to the length of and within the ditch formed in step (1); and

(8) installing a vertically disposed upwardly opening manhole in the excavation of step (5).

3. The method of claim 1, and further including the step of:

(6) arranging spaced apart digging teeth on each side digger whereby the teeth are circumferentially disposed in spaced apart rows with respect to each other.

References Cited UNITED STATES PATENTS 824,839 7/1906 Bentson 37-87 1,299,826 4/1919 Dewey 37-87 1,477,940 12/1923 Brown 37-87 1,569,091 1/1926 Kean 37-87 1,858,727 5/1932 Bentson 37-87 2,984,025 5/1961 Winn 37-97 2,166,632 7/1939 Hardesty et a1. 52-20 XR 2,656,800 10/1953 Reising 37-86 XR ROBERT E. PULFREY, Primary Examiner C. D. CROWDER, Assistant Examiner US. Cl. X.R. 

